Terraform and Ansible are both popular tools used in infrastructure automation
They have distinct purposes and approaches:
Terraform:
- Focus: Infrastructure as Code (IaC)
- Purpose: Provisioning and managing infrastructure across various cloud providers and on-premises environments.
- Configuration: Declarative. You define the desired state of your infrastructure (e.g., VMs, networks, storage) and Terraform orchestrates the creation and management.
- Configuration Language: HashiCorp Configuration Language (HCL) – Focused on describing infrastructure resources.
- State Management: Stores the state of your infrastructure (created resources) in a Terraform state file.
- Mutability: Terraform is primarily for immutable infrastructure. If changes are needed, you modify the configuration and re-run Terraform to recreate the resources with the desired state.
Ansible:
- Focus: Configuration Management and Automation
- Purpose: Configure and manage existing infrastructure, including servers, network devices, containers, and applications.
- Configuration: Declarative or Procedural. You can define the desired configuration state or specific actions to be executed.
- Configuration Language: YAML (often with Jinja2 templating) – More flexible for complex tasks and conditional logic.
- State Management: Ansible itself doesn’t maintain a persistent state by default. It relies on idempotent tasks (tasks that produce the same result on every execution) to achieve the desired configuration.
- Mutability: Ansible excels at mutable infrastructure. You can make changes to existing configurations without necessarily recreating the entire infrastructure.
Here’s a table summarizing the key differences:
| Feature | Terraform | Ansible |
|---|---|---|
| Focus | Infrastructure as Code (IaC) | Configuration Management and Automation |
| Purpose | Provisioning and managing infrastructure | Configure and manage existing infrastructure |
| Configuration Style | Declarative | Declarative or Procedural |
| Configuration Language | HCL | YAML (often with Jinja2 templating) |
| State Management | Stores state in Terraform state files | Relies on idempotent tasks, no persistent state by default |
| Mutability | Primarily immutable | More suitable for mutable infrastructure |
Choosing the Right Tool:
- Use Terraform when:
- You need to provision and manage infrastructure across different environments.
- You prefer a declarative approach for defining the infrastructure state.
- Immutable infrastructure is desired.
- Use Ansible when:
- You need to configure existing infrastructure, including servers, network devices, containers, etc.
- You prefer flexibility with declarative or procedural configuration options.
- You need to manage mutable infrastructure and make changes to existing configurations.
Additionally:
- They can be used together. Terraform can provision the infrastructure, and Ansible can configure the software and applications running on that infrastructure.
- Other tools like Chef or Puppet offer similar functionalities to Ansible for configuration management.
Image credit
Ansible.com, Public domain, via Wikimedia Commons
Terraform by Hashicorp
